Display turns black when an object that's potentially being instantiate every frame is in view. Settings button will also disappear. When the instantiate object is out of sight, the view turns normal. Settings button will appear.

Unity 5 rendering issues: As of Unity build 5.0.0f4, the following steps should be taken to fix or ameliorate any rendering issues, such
as an all-black screen, flashing textures, or non-stereo views:
Enable the Development Build option in the Build dialog. This seems to fix various rendering glitches, like flashing textures.

The root cause of the rendering glitches is under analysis, with assistance from Unity.

Note: If you are using any Image Effects, make sure that StereoController's Direct Render property is set to false. Check if
that fixes the issue first.